Green Man Gaming over the weekend, starting on Friday 12:00 GMT, will be releasing four different games available for download in 24 hour intervals. The only catch is that you will need a Green Man Gaming account and a Playfire account and link the two accounts.

Game Release Schedule:

On Friday February 8 at 12:00 GMT (7 AM Eastern), Zombies, currently priced at $3.99 USD, will be free for 24 hours.

http://www.youtube.com/watch?v=zYXozx3bVII

On Saturday February 9 at 12:00 GMT (7 AM Eastern), Ninja Blade, currently priced at $8.99 USD, will be free for 24 hours.

http://www.youtube.com/watch?v=8a6M9Y5xHl0

On Sunday February 10 at 12:00 GMT (7 AM Eastern), Unstoppable Gorg, currently priced at $9.99 USD, will be free for 24 hours.

If you download a game during the period its free, it's counted a normal digital purchase and you can get to keep it. I should have added that to the original post. I apologize if that caused any confusions.